A typical image forming apparatus has a resistor that suppresses influence of abnormal discharges such as spark discharges. The resistor suppresses occurrence of spark discharges between, for example, a transfer sheet and a photoconductor.
Meanwhile, such a resistor can be adopted in configuration that includes: a charger having a discharge wire and a grid, i.e. a scorotron charger; and a circuit that is connected to the grid and detects abnormal discharge due to dust on the wire of the charger. When adopted in such configuration, the resistor can suppress abnormal discharge energy.
However, as a next step of improvement, there is a need for reducing the abnormal discharge energy while simplifying the circuit configuration having the abnormal-discharge detection circuit connected to the grid of the charger.